A048442 Take the first n numbers written in base 11, concatenate them, then convert from base 11 to base 10.

1, 13, 146, 1610, 17715, 194871, 2143588, 23579476, 259374245, 2853116705, 345227121316, 41772481679248, 5054470283189021, 611590904265871555, 74002499416170458170, 8954302429356625438586, 1083470593952151678068923, 131099941868210353046339701

Offset

1,2

Links

Vincenzo Librandi, Table of n, a(n) for n = 1..200

Example

a(11) = (1)(2)(3)(4)(5)(6)(7)(8)(9)(A)(10) = 123456789A10_11 = 345227121316.

Mathematica

If[STARTPOINT==1, n={}, n=Flatten[IntegerDigits[Range[STARTPOINT-1], 11]]]; Table[AppendTo[n, IntegerDigits[w, 11]]; n=Flatten[n]; FromDigits[n, 11], {w, STARTPOINT, ENDPOINT}] (* Dylan Hamilton, Aug 11 2010 *)
f[n_]:= FromDigits[Flatten@IntegerDigits[Range@n, 11], 11]; Array[f, 20] (* Vincenzo Librandi, Dec 30 2012 *)

Prog

(PARI) { cuo=0;
for(ixp=1, 18, casi = ixp; cvst=0;
while(casi != 0,
cvd = casi%11; cvst=100*cvst + cvd + 1; casi = (casi - cvd) / 11 );
while(cvst !=0, ptch = cvst%100;
cuo=cuo*11+ptch-1; cvst = (cvst - ptch) / 100 ); print1(cuo, ", "))}
\\ Douglas Latimer, May 09 2012
(Magma) [n eq 1 select 1 else Self(n-1) * 11^(1+Ilog(11, n)) + n: n in [1..20]]; // Vincenzo Librandi, Dec 30 2012

Crossrefs

Cf. A014881.

Concatenation of first n numbers in other bases: 2: A047778, 3: A048435, 4: A048436, 5: A048437, 6: A048438, 7: A048439, 8: A048440, 9: A048441, 10: A007908, 11: this sequence, 12: A048443, 13: A048444, 14: A048445, 15: A048446, 16: A048447.

Sequence in context: A199023 A152585 A014881 * A353107 A051524 A110748

Adjacent sequences: A048439 A048440 A048441 * A048443 A048444 A048445

Keyword

nonn,base,easy

Author

Patrick De Geest, May 15 1999

Extensions

1 more term from Douglas Latimer, May 10 2012

Status

approved